In a membrane biofilm reactor (MBfR), a membrane is used to both support a biofilm and to transport a gas to the biofilm. Membrane biofilm reactors were recently reviewed by Martin and Nerenberg in “The membrane biofilm reactor (MBfR) for water and wastewater treatment: Principles, applications, and recent developments” (Bioresour. Technol. 2012). Membrane-aerated biofilm reactors (MABR) are a subset of MBfRs in which an oxygen containing gas is used. MABRs were reviewed by Syron and Casey in “Membrane-Aerated Biofilms for High Rate Biotreatment: Performance Appraisal, Engineering Principles, Scale-up, and Development Requirements” (Environmental Science and Technology, 42(6): 1833-1844, 2008).
U.S. Pat. No. 7,169,295 describes a membrane supported biofilm reactor with modules having fine hollow fiber membranes. The membranes are made from dense wall polymethyl pentene (PMP) used in tows or formed into a fabric. The membranes are potted in a header of a module to enable oxygen containing gas to be supplied to the lumens of the hollow fibers. The reactor may be used to treat wastewater. Mechanical, chemical and biological methods are used to control the thickness of the biofilm. International Publication Number 2008/130885 describes a hybrid process with suspended biomass and a membrane supported biofilm.